Question

SAT scores are distributed with a mean of 1,500 and a standard deviation of 314. You are interested in estimating the average SAT score of first year students at your college. If you would like to limit the margin of error of your confidence interval to 25 points with 95 percent confidence, how many students should you sample? (Round up to a whole number of students.)

Answer 1

Given that,

standard deviation =s =   =314

Margin of error = E = 25

At 99% confidence level the z is,

= 1 - 99%

= 1 - 0.99 = 0.01

/2 = 0.005

Z/2 = 2.58

sample size = n = [Z/2* / E] 2

n = ( 2.58* 314 / 25 )2

n =1050.07

Sample size = n =1051

SOME IT SHOW ANSWER IS 1051